Research on Preheating of Titanium Alloy Powder in Electron Beam Melting Technology

摘要:

研究了电子束熔化快速成形技术中的钛合金粉末预热工艺，并对粉末预热后的颗粒联接方式进行了分析。结果表明，当Ti6Al4V粉末由电子束连续扫描快速预热升温至600 ℃以上，粉末颗粒中高比表面积的细小颗粒，由于高能量密度电子束作用将全部或部分熔化而充当粉末颗粒联接团聚的粘结剂，使得预热区域的粉末颗粒聚团结块。该粉末团聚体不仅能有效抵挡高速电子束流的冲击而使熔化成形的表面粉末不飞溅，而且也能避免成形表面粉末颗粒熔化时的球化效应。以Ti6Al4V粉末为原料并充分预热每层的成形粉末，制备了层间熔合良好并且力学性能优异的Ti6Al4V柱状试样。

Abstract:

The titanium alloy powder preheating process in electron beam melting (EBM) was investigated, and the connection mode among powder particles after preheating was analyzed. The results show that when the Ti6Al4V powder is preheated to above 600 °C during EBM process, a powder aggregation is formed. The sintering mechanism is that small particles partially or completely melt and play the role of binder to bond the majority of big particles together; this will be not only to help the particles to hold their places, withstanding the impact force of electron beam, but also to prevent the spheroidization effect in the prototyped surface. Using Ti6Al4V powder as starting material and adopting complete preheating of the powder layer, the column samples with full interlayer bonding and excellent mechanical properties are produced.